mei: gsc: add runtime pm handlers

Implement runtime handlers for mei-gsc, to track
idle state of the device properly.

CC: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220419193314.526966-5-daniele.ceraolospurio@intel.com

drivers/misc/mei/gsc-me.c

@@ -159,7 +159,72 @@ static int __maybe_unused mei_gsc_pm_resume(struct device *device)
 	return 0;
 }
 
-static SIMPLE_DEV_PM_OPS(mei_gsc_pm_ops, mei_gsc_pm_suspend, mei_gsc_pm_resume);
+static int __maybe_unused mei_gsc_pm_runtime_idle(struct device *device)
+{
+	struct mei_device *dev = dev_get_drvdata(device);
+
+	if (!dev)
+		return -ENODEV;
+	if (mei_write_is_idle(dev))
+		pm_runtime_autosuspend(device);
+
+	return -EBUSY;
+}
+
+static int  __maybe_unused mei_gsc_pm_runtime_suspend(struct device *device)
+{
+	struct mei_device *dev = dev_get_drvdata(device);
+	struct mei_me_hw *hw;
+	int ret;
+
+	if (!dev)
+		return -ENODEV;
+
+	mutex_lock(&dev->device_lock);
+
+	if (mei_write_is_idle(dev)) {
+		hw = to_me_hw(dev);
+		hw->pg_state = MEI_PG_ON;
+		ret = 0;
+	} else {
+		ret = -EAGAIN;
+	}
+
+	mutex_unlock(&dev->device_lock);
+
+	return ret;
+}
+
+static int __maybe_unused mei_gsc_pm_runtime_resume(struct device *device)
+{
+	struct mei_device *dev = dev_get_drvdata(device);
+	struct mei_me_hw *hw;
+	irqreturn_t irq_ret;
+
+	if (!dev)
+		return -ENODEV;
+
+	mutex_lock(&dev->device_lock);
+
+	hw = to_me_hw(dev);
+	hw->pg_state = MEI_PG_OFF;
+
+	mutex_unlock(&dev->device_lock);
+
+	irq_ret = mei_me_irq_thread_handler(1, dev);
+	if (irq_ret != IRQ_HANDLED)
+		dev_err(dev->dev, "thread handler fail %d\n", irq_ret);
+
+	return 0;
+}
+
+static const struct dev_pm_ops mei_gsc_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(mei_gsc_pm_suspend,
+				mei_gsc_pm_resume)
+	SET_RUNTIME_PM_OPS(mei_gsc_pm_runtime_suspend,
+			   mei_gsc_pm_runtime_resume,
+			   mei_gsc_pm_runtime_idle)
+};
 
 static const struct auxiliary_device_id mei_gsc_id_table[] = {
 	{